Price movements have grabbed the headlines in recent weeks. Commodity prices are falling, and as always, there are various arguments about the reasons this time. The implications are serious, so the debates are warranted. But the more pressing issue is recent movement in the general price level. Overall price growth has weakened lately, and there is renewed worry about disinflation and deflation (the dreaded Ds). Five years beyond the crisis, and we are still worried about this? What's going on?

Imagine that you found out tomorrow that your bank was going to start charging a storage fee on your cash. What would you do? I think most people would withdraw their money from those accounts and keep it in cash. It's unlikely they would spend or invest it, even though that's the purpose of imposing negative interest rates.

In an unprecedented move, the Fed undertook an extraordinary experiment in monetary policy. Unable to further target an interest rate, already at zero, the Fed began announcing a quantity of cash that it would inject into the financial system by purchasing large numbers of government bonds and other highly-rated securities, and replacing them with cash.